In the introduction, we claimed that the gravitational potential energy could be ignored if the displacement used in the elastic potential energy was measured from the hanging equilibrium position. first, write the total mechanical energy (kinetic, gravitational potential, and elastic potential energy) in terms of a coordinate system, position measured upward and labeled y, whose origin is located at the bottom of the relaxed spring of a constant, k (no force applied). labquest 17 17 - 6 physics with vernier then determine the equilibrium position, h, when a mass, m, is suspended from the spring. this will be the new origin for a coordinate system with position labeled z. write a new expression for total energy as a function of z. show that when the energy is written in terms of z rather than y, the gravitational potential energy term cancels out.